linux-kernel - Re: [PATCH V3 4/7] cpufreq: Add a notification message that the highest perf has changed

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Message-ID: <20230824110440.ziat2zlxcvq7ar6z@BLR-5CG13462PL.amd.com>
Date:   Thu, 24 Aug 2023 16:48:43 +0530
From:   Wyes Karny <wyes.karny@....com>
To:     Meng Li <li.meng@....com>
CC:     Wyes Karny <wyes.karny@....com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Huang Rui <ray.huang@....com>, <linux-pm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
        <linux-acpi@...r.kernel.org>,
        Shuah Khan <skhan@...uxfoundation.org>,
        <linux-kselftest@...r.kernel.org>,
        Nathan Fontenot <nathan.fontenot@....com>,
        Deepak Sharma <deepak.sharma@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Mario Limonciello <mario.limonciello@....com>,
        Shimmer Huang <shimmer.huang@....com>,
        Perry Yuan <Perry.Yuan@....com>,
        Xiaojian Du <Xiaojian.Du@....com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH V3 4/7] cpufreq: Add a notification message that the highest perf has changed

On 24 Aug 10:12, Meng Li wrote:
> ACPI 6.5 section 8.4.6.1.1.1 specifies that Notify event 0x85 can be
> emmitted to cause the the OSPM to re-evaluate the highest performance
> register. Add support for this event.
> 
> Signed-off-by: Meng Li <li.meng@....com>
> Link: https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html?highlight=cppc#cpc-continuous-performance-control
> ---
>  drivers/acpi/processor_driver.c |  6 ++++++
>  drivers/cpufreq/cpufreq.c       | 13 +++++++++++++
>  include/linux/cpufreq.h         |  4 ++++
>  3 files changed, 23 insertions(+)
> 
> diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
> index 4bd16b3f0781..29b2fb68a35d 100644
> --- a/drivers/acpi/processor_driver.c
> +++ b/drivers/acpi/processor_driver.c
> @@ -27,6 +27,7 @@
>  #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
>  #define ACPI_PROCESSOR_NOTIFY_POWER	0x81
>  #define ACPI_PROCESSOR_NOTIFY_THROTTLING	0x82
> +#define ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED	0x85
>  
>  MODULE_AUTHOR("Paul Diefenbaugh");
>  MODULE_DESCRIPTION("ACPI Processor Driver");
> @@ -83,6 +84,11 @@ static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
>  		acpi_bus_generate_netlink_event(device->pnp.device_class,
>  						  dev_name(&device->dev), event, 0);
>  		break;
> +	case ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED:
> +		cpufreq_update_highest_perf(pr->id);
> +		acpi_bus_generate_netlink_event(device->pnp.device_class,
> +						  dev_name(&device->dev), event, 0);
> +		break;
>  	default:
>  		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
>  		break;
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 50bbc969ffe5..842357abfae6 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2675,6 +2675,19 @@ void cpufreq_update_limits(unsigned int cpu)
>  }
>  EXPORT_SYMBOL_GPL(cpufreq_update_limits);
>  
> +/**
> + * cpufreq_update_highest_perf - Update highest performance for a given CPU.
> + * @cpu: CPU to update the highest performance for.
> + *
> + * Invoke the driver's ->update_highest_perf callback if present
> + */
> +void cpufreq_update_highest_perf(unsigned int cpu)
> +{
> +	if (cpufreq_driver->update_highest_perf)
> +		cpufreq_driver->update_highest_perf(cpu);
> +}
> +EXPORT_SYMBOL_GPL(cpufreq_update_highest_perf);
> +
>  /*********************************************************************
>   *               BOOST						     *
>   *********************************************************************/
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index 9bf94ae08158..58106b3d9183 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -232,6 +232,7 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
>  void refresh_frequency_limits(struct cpufreq_policy *policy);
>  void cpufreq_update_policy(unsigned int cpu);
>  void cpufreq_update_limits(unsigned int cpu);
> +void cpufreq_update_highest_perf(unsigned int cpu);
>  bool have_governor_per_policy(void);
>  bool cpufreq_supports_freq_invariance(void);
>  struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
> @@ -377,6 +378,9 @@ struct cpufreq_driver {
>  	/* Called to update policy limits on firmware notifications. */
>  	void		(*update_limits)(unsigned int cpu);
>  
> +	/* Called to update highest performance on firmware notifications. */
> +	void		(*update_highest_perf)(unsigned int cpu);
> +

Can we use the existing `update_limits` callback?

Thanks,
Wyes
>  	/* optional */
>  	int		(*bios_limit)(int cpu, unsigned int *limit);
>  
> -- 
> 2.34.1
>